1. Field of the Invention
The present invention relates to an image capturing system.
2. Description of the Related Art
Some digital single-lens reflex cameras perform an image capturing operation using both a focal-plane shutter (to be referred to as a mechanical shutter hereinafter) and an electronic shutter, as disclosed in Japanese Patent Laid-Open No. 11-41523.
In the technique described in Japanese Patent Laid-Open No. 11-41523, the mechanical shutter runs upward. An electromagnet holds, by its attractive force, the mechanical front and rear curtains of the mechanical shutter at the running start position. In many cases, the mechanical shutter runs upward using a spring force. Hence, the running mechanical shutter may receive a load of gravity. Since this makes the running speed of the mechanical shutter unstable, the driving mechanism of the mechanical shutter readily changes over time and causes a deterioration in the operation durability.
To suppress the load due to gravity received by the running mechanical shutter, the image sensing device disclosed in Japanese Patent Laid-Open No. 11-41523 may be inverted to cause the mechanical shutter to run downward. In the technique described in Japanese Patent Laid-Open No. 11-41523, the scanning direction to reset each pixel in the image sensing device is the same as the scanning direction to read out a signal from each pixel. An optical image of an object is formed on the photoelectric conversion element as an image point-symmetrical to the actual object sequentially downward in the pixel array via the lens and mechanical shutter. Hence, pixel signals are read out sequentially downward in the pixel array. Since the captured image is displayed sequentially from the lower to upper parts of the object, it may appear unnatural to the viewer.